In a telecommunications network having a plurality of interconnected nodes, certain portions of the network include subsets of interconnected nodes that may be defined to have the ability to dynamically restore traffic disrupted along paths interconnecting those nodes. Each subset of such nodes may be referred to as a distributed restoration network within the telecommunications network or simply a distributed restoration domain, or more specifically a dynamic transmission network restoration (DTNR) domain. A distributed restoration algorithm (DRA) is stored in each node of the distributed restoration domain.
As is well known, different paths may be effected in the telecommunications network through which traffic signals are routed. A path may be established within the telecommunications network, or within any restoration domain within the network. No matter how long or short each path is, the one thing that remains constant is that each path has to have two end points, i.e., two end nodes.
In a distributed restoration domain, once a path is formed connecting two end nodes, which may also be referred to as access/egress nodes within the domain, no matter how many intermediate nodes and links are used to forge the path, the two end nodes within the restoration domain through which the path extends remain the same. Thus, given the ability of the nodes within the restoration domain to dynamically restore disrupted traffic by finding alternate routes, the traffic traversing between the two end nodes may in fact be routed differently by different interconnected intermediate nodes. The integrity of any route that connects the two end nodes therefore needs to be verified, particularly when there may in fact be different routes connecting the two end nodes. But such path verification must be done non-obtrusively, as equipment and facilities along the path may be affected by such path verification messages. Moreover, such verification of the integrity of the path has to be continuous, at least with respect to the traffic data that is being conveyed along the path, so that if the path is no longer robust, only a minimal amount of data is lost.
It is therefore an objective of the present invention to provide a method and a network therefor wherein path verification messages can be discretely integrated to or carried by the traffic signals traversing along the path.